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Best tube amp for electrostatic speakers

For over 35 years I've almost exclusively used either ribbons or electrostats with solid state amplification and have been generally happy with the sound. Over the last several years, though, my hearing has become somewhat degraded and more sensitive to certain frequencies. The frequencies which seem to cause the most discomfort occur in the 1400 to 1900Hz range and come across as "bright" to my hearing. After researching this matter and having been given some expert advice, I've decided to pursue the idea of replacing my present amplification equipment with tube based gear.

The purpose of this post, then, is to solicit advice regarding the best approach to making this decision based on the following information: the current basic equipment is Shanling Solid state CD player, Peachtree Audio Nova used as preamp, two DBX 1531 EQ's to help compensate for age related hearing loss, Peachtree 220 amp, Silversonic T114 cable and Martin Logan Ethos speakers.

The listening area is our living room measuring 15 by 22 feet with my listening position 16 feet from the plane of the 2 speakers which are positioned 11 feet apart measured center to center. Located between the 2 speakers is an entertainment center which is about 9 feet wide. My listening interests are varied from solo guitar and light jazz to occasional orchestral music. I don't generally listen at high volumes and am not particularly interested in strong bass except for the rare action movie background.

Unless not advisable for some reason, I would like to keep the Peachtree Nova as a preamp because of the significant latitude for source connection and what seems to have a decent internal DAC. If this option would substantially defeat the purpose of the intended modification I would work around it. I can no longer deal with sounds that are "bright" which I now find uncomfortable but detailed sound is very important.

So, the questions are: is the move to tubes the best option and, if so, what might be some reasonably priced amps that could accomplish the goal. This, of course, would take into consideration room size, etc. for determining power requirements. If there are other more practical and less expensive options to consider, I would appreciate that advice as well.
128x128broadstone

Showing 4 responses by almarg

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almarg
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Thanks very much, Schubert. I appreciate the nice words. To answer your question, yes I have BSEE and MSEE degrees, and 33 years experience designing and managing design of analog and digital circuits for defense electronics. I'm now happily retired :-)

Best regards,
-- Al
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Regarding the measurements cited in George's two posts just above, I would emphasize that the frequency responses and rolloffs that are described apply to electrical signals at the amplifier output/speaker input, not to the acoustic output of the speaker. As I said earlier:
01-14-15: Almarg
... while it is true that when working into an electrostatic such as the Ethos the use of a tube amp, especially one which uses minimal or no global feedback, is likely to result in voltage vs. frequency characteristics at the input terminals of the speaker that are less flat than would result from the use of most solid state amps, it by no means necessarily follows that the frequency response characteristics of the acoustic output of the speaker will be flatter in the latter case. As can be seen in the comments by Ralph (Atmasphere).
The successful pairing of tube amps with electrostatics by many experienced audiophiles, as can be seen in system descriptions and posts here and elsewhere, confirms the importance of distinguishing between flat frequency response into the speaker, and flat frequency response out of the speaker. They don't necessarily go hand in hand, particularly in the case of electrostatics. IMO.

Regards,
-- Al
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almarg
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Bruce (Bifwynne), +1 to your post just above, and to George's reference to EPDR and his characterization of the S-5 as a challenging load.

Regarding the on-going disagreements about the suitability of tube amps for driving Martin-Logans and other electrostatics, perhaps we should just declare an impasse at this point. Also, I would refer those interested to this thread, in which all of the present protagonists, and many other knowledgeable folks as well, argued the same issues over the course of a three-page thread.

OK, so much for non-partisanship :-) In that three-page thread I would nominate as the tie-breaking perspective the posts by member Frogman, who as a long-time professional classical and jazz musician, as well as a highly experienced audiophile, unquestionably has one of the most impressive combinations extant of audiophile and musical backgrounds.

Best regards,
-- Al
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01-13-15: Georgelofi
But from what was said to get the very best from the ML Ethos you need an amp that can that can deliver good current down to at least 2ohms, so it stays flat over the frequency range, and not start behaving like a tone control at different load impedances.

That means "close" to doubling the 8ohm spec wattage to 4ohms and again doubling to 2ohms

01-14-15: Georgelofi
The Peachtree 220 from what I found can almost double into 4ohm giving 400watt but I can find nothing into 2ohm. If it gave 600 or 700 into 2ohm then this is the sort of amp that would not whimp out into the 1ohm of the the Ethos. And at 72 years old you don't want an amp that is going to curtail the upper mid/highs, because it's here where the Ethos are that heavy load of 2 to 1ohm, that will make a whimpy amp sound soft and dull.
In fairness it should be pointed out that there are many audiophiles and designers who would disagree with these statements, on both theoretical and empirical grounds. The relatively high output impedance/low damping factor of most tube amps, especially those using little or no global feedback, and the inability of such amps to double power into halved load impedances, will in combination with the impedance vs. frequency characteristics of the Ethos and most other electrostatics certainly result in less emphasis of the upper octaves compared to the presentation that would result with most solid state amps. However which of those presentations is more true to the source material, and which of those presentations is more subjectively preferable, and which of those presentations is less likely to trigger Jim's (Broadstone's) specific hearing issues, are separate questions.

And while it is true that when working into an electrostatic such as the Ethos the use of a tube amp, especially one which uses minimal or no global feedback, is likely to result in voltage vs. frequency characteristics at the input terminals of the speaker that are less flat than would result from the use of most solid state amps, it by no means necessarily follows that the frequency response characteristics of the acoustic output of the speaker will be flatter in the latter case. As can be seen in the comments by Ralph (Atmasphere).

Also, regarding the amp's ability to deliver adequate current into low impedances, it should be kept in mind that most music contains far less energy in the treble region than at lower frequencies, especially in the upper part of the treble region where the speaker impedance becomes really low in the case of the Ethos and many other electrostatics.

Regards,
-- Al
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